Display apparatus and backlight unit thereof

ABSTRACT

A display apparatus and a backlight unit thereof. The display apparatus includes: a frame; a plurality of light emitting diodes regularly arranged on the frame; an optical part disposed above the plurality of light emitting diodes and including a display panel and at least one of a phosphor sheet and an optical sheet; and a light guide plate disposed between the frame and the optical part to cover the plurality of light emitting diodes, wherein the light guide plate is formed with light source grooves placed corresponding to locations of the plurality of light emitting diodes, respectively, such that light emitted from each of the light emitting diodes enters the corresponding light source groove to spread light in a lateral direction when the light enters the light guide plate, thereby enabling use of a direct type backlight unit without a separate lens.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from and the benefit of U.S.Provisional Patent Application No. 62/421,454, filed on Nov. 14, 2016;U.S. Provisional Patent Application No. 62/422,157, filed on Nov. 15,2016; and U.S. Provisional Patent Application No. 62/436,553, filed onDec. 20, 2016, which are each hereby incorporated by reference for allpurposes as if fully set forth herein.

BACKGROUND Field

Exemplary embodiments of the inventive concepts relate to a displayapparatus and a backlight unit thereof, and more particularly, to adisplay apparatus emitting light through a direct type backlight and abacklight unit thereof.

Discussion of the Background

Recently, there is increasing demand for making a display apparatus asthin as possible. Accordingly, for a liquid crystal display (LCD), anedge type backlight unit, including a light source disposed at one sidethereof, is generally used.

However, a liquid crystal display including such an edge type backlightunit cannot realize high dynamic range (HDR) imaging, which is a methodof producing images on a display screen so as to allow a viewer toexperience a sense of viewing an actual scene through the images. Inorder to realize HDR, it is necessary to realize a difference inluminance of light emitted through the display apparatus depending uponlocations on a display screen. However, the liquid crystal displayemploying the edge type backlight unit cannot realize a difference inluminance of light depending upon locations on the display screen.

Accordingly, various studies have been made to realize HDR throughimplementation of an active matrix type using a direct type backlightunit. One example of these studies is disclosed in Korean PatentLaid-open Publication No. 10-2016-0051566 (2016 May 11, hereinafter“Prior Document”). However, this publication discloses a displayapparatus using a direct type backlight unit and a lens disposed tospread light emitted from a light emitting diode in a lateral direction.However, use of the lens provides a limitation in reduction in thicknessof the display apparatus due to the thickness of the lens.

Although a backlight unit typically employs a lens in order to realizeuniform surface light throughout the backlight unit by allowing lightemitted from the light emitting diode to spread in the lateraldirection, it is difficult to improve uniformity of a surface lightsource even when using the lens.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the inventive conceptsand therefor it may contain information that does not constitute priorart.

SUMMARY

Exemplary embodiments of the inventive concepts provide a displayapparatus that can reduce a thickness thereof while employing a directtype backlight and a backlight unit thereof.

Exemplary embodiments of the inventive concepts provide a displayapparatus that can improve uniformity of a surface light source whileemploying a direct type backlight.

Additional features of the inventive concepts will be set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the inventive concepts.

An exemplary embodiment of the inventive concepts discloses a displayapparatus including: a frame; a plurality of light emitting diodesregularly arranged on the frame; an optical part disposed above theplurality of light emitting diodes and including a display panel and atleast one of a phosphor sheet and an optical sheet; and a light guideplate disposed between the frame and the optical part to cover theplurality of light emitting diodes. The light guide plate is formed withlight source grooves placed corresponding to locations of the pluralityof light emitting diodes, respectively, such that light emitted fromeach of the light emitting diodes enters the corresponding light sourcegroove.

The light source groove may have a concave shape and include a flatupper surface.

The light guide plate may include a regular or irregular roughnessformed on an upper surface thereof. The roughness may have a thicknessof 5 μm to 500 μm.

The light guide plate may have a thickness of 0.5 mm to 3.0 mm and thelight source groove may have a depth corresponding to 70% to 80% of athickness of the light guide plate.

Each of the light emitting diodes may be a light emitting diode chip.

Each of the light emitting diodes may be a light emitting diode package.Here, the light emitting diode package may include a light emittingdiode chip; and a reflector disposed on an upper surface of the lightemitting diode chip and reflecting at least part of light emitted fromthe light emitting diode chip. The reflector may include a distributedBragg reflector. The reflector may have a transmittance of 0% to 80%with respect to light emitted from the light emitting diode chip.

The light emitting diode package may further include a molding partdisposed to cover upper and side surfaces of the light emitting diodechip and the reflector.

The molding part may have a smaller thickness from the upper surface ofthe reflector to an upper surface of the molding part than a width fromthe side surface of the light emitting diode chip to a side surface ofthe molding part.

The width of the molding part from the side surface of the lightemitting diode chip to the side surface of the molding part may be 1.5to 4 times the thickness of the molding part from the upper surface ofthe reflector to the upper surface of the molding part.

The molding part may include at least one of at least one type ofphosphor and at least one type of light diffuser.

The light guide plate may have a light exit groove formed on an uppersurface thereof and have a concave shape. The light exit groove may havea conical shape.

The display apparatus may further include a reflection sheet interposedbetween the light guide plate and the frame and reflecting light insidethe light guide plate in an upward direction. The reflection sheet maybe separated from the light emitting diode package.

The light guide plate may have a lower surface stepped from a distal endof the light source groove and an inclined surface between the lightsource groove and the lower surface, and the lower surface may adjointhe reflection sheet.

The lower surface may be a second lower surface and the light guideplate may further include a first lower surface between the inclinedsurface and the light source groove.

Another exemplary embodiment of the inventive concepts includes abacklight unit of a display apparatus including: a plurality of lightemitting diodes; and a light guide plate covering the plurality of lightemitting diodes and spreading light emitted from the plurality of lightemitting diodes. The light guide plate is formed with light sourcegrooves placed corresponding to locations of the plurality of lightemitting diodes, respectively, such that light emitted from each of thelight emitting diodes enters the corresponding light source groove.

The light source groove may include a flat upper surface and the lightguide plate may include a regular or irregular roughness formed on anupper surface thereof.

The light source groove may have a depth corresponding to 70% to 80% ofa thickness of the light guide plate.

The light guide plate may have a light exit groove formed on an uppersurface thereof and having a concave shape. The light exit groove mayhave a conical shape.

The backlight unit may further include a reflection sheet disposed on alower surface of the light guide plate and reflecting light inside thelight guide plate in an upward direction.

The light guide plate may include a first lower surface extending fromthe light source groove, a second lower surface stepped from the firstlower surface, and an inclined surface between the first lower surfaceand the second lower surface, and the second lower surface may adjointhe reflection sheet.

Another exemplary embodiment of the inventive concepts discloses adisplay apparatus including: a frame; a plurality of light emittingdiode packages regularly arranged on the frame; an optical part disposedabove the plurality of light emitting diode packages and including adisplay panel and at least one of a phosphor sheet and an optical sheet;and a lens disposed between the frame and the optical part to cover eachof the light emitting diode packages and spreading light emitted fromthe corresponding light emitting diode package. Each of the lightemitting diode packages includes a light emitting diode chip; and areflector disposed on an upper surface of the light emitting diode chipand reflecting at least part of light emitted from the light emittingdiode chip.

The lens may include a lower surface having a concave portion defining alight incident face through which light enters the lens; and an uppersurface through which light exits the lens, and the light emitting diodepackage may be disposed inside the concave portion of the lens.

The light incident face of the lens may include an upper end portion anda side surface extending from the upper end portion to an entrance ofthe concave portion, and the concave portion may have a width graduallydecreasing from the entrance thereof to the upper end portion.

The side surface may be an inclined surface having a constantinclination from the entrance of the concave portion to the upper endportion or a curved inclined surface having a gradually decreasinginclination from the entrance of the concave portion to the upper endportion.

The upper end portion may be a flat surface or a curved surface.

The reflector may include a distributed Bragg reflector. The reflectormay have a transmittance of higher than 0% to less than 100% withrespect to light emitted from the light emitting diode chip.

The light emitting diode package may further include a molding partdisposed to cover upper and side surfaces of the light emitting diodechip and the reflector.

The molding part may include at least one of at least one type ofphosphor and at least one type of light diffuser.

According to exemplary embodiments, a light guide plate of the backlightunit includes a light source groove placed corresponding to a locationof a light emitting diode package so as to spread light in a lateraldirection when the light enters the light guide plate, thereby enablinguse of a direct type backlight unit without a separate lens.

In addition, the exemplary embodiments of the inventive concepts providea thinner direct type backlight than a typical direct type backlightunit through elimination of a separate lens, thereby enabling reductionin thickness of a display apparatus.

According to exemplary embodiments, as a backlight unit of a displayapparatus, light emitting diode packages each having a reflectordisposed on a light emitting diode chip are coupled to lenses,respectively, thereby improving uniformity of surface light with respectto light emitted from a plurality of light emitting diode packages.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the inventive concepts asclaimed.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosed technology, and are incorporated in andconstitute a part of this specification, illustrate exemplaryembodiments of the disclosed technology, and together with thedescription serve to describe the principles of the disclosedtechnology.

FIG. 1A is a top view of a display apparatus according to a firstexemplary embodiment of the inventive concepts.

FIG. 1B is a bottom view of the display apparatus according to the firstexemplary embodiment of the inventive concepts.

FIG. 2A and FIG. 2B are cross-sectional views of the display apparatusaccording to the first exemplary embodiment of the inventive concepts.

FIG. 3 is a sectional view of a light guide plate of the displayapparatus according to the first exemplary embodiment of the inventiveconcepts.

FIG. 4 is a graph comparing light emission through the light guide platewhen light is emitted from light emitting diode packages according tothe first exemplary embodiment of the inventive concepts.

FIG. 5 is a sectional view of a light emitting diode package of thedisplay apparatus according to the first exemplary embodiment of theinventive concepts.

FIG. 6 is a graph comparing light emission from the light emitting diodepackage of the display apparatus according to the exemplary embodimentof the inventive concepts.

FIG. 7 is a sectional view of a light guide plate of a display apparatusaccording to a second exemplary embodiment of the inventive concepts.

FIG. 8 shows simulation images of light emitted from the displayapparatus according to the second exemplary embodiment of the inventiveconcepts.

FIG. 9A is a top view of a display apparatus according to one exemplaryembodiment of the inventive concepts.

FIG. 9B is a bottom view of the display apparatus according to theexemplary embodiment of the inventive concepts.

FIG. 10A and FIG. 10B are cross-sectional views of the display apparatusaccording to the exemplary embodiment of the inventive concepts.

FIG. 11 is a sectional view of a lens of the display apparatus accordingto the exemplary embodiment of the inventive concepts.

FIG. 12 is a sectional view of a light emitting diode package accordingto one exemplary embodiment of the inventive concepts.

FIG. 13 shows an image of light emitted from a plurality of lightemitting diode packages, explaining uniformity of light emitted from thedisplay apparatus according to the exemplary embodiment of the inventiveconcepts.

FIG. 14 shows images and graphs comparing uniformity of light emittedfrom the display apparatus according to the exemplary embodiment of theinventive concepts depending upon structure of light emitting diodepackages.

FIG. 15 shows graphs comparing directional characteristics of lightemitted from the display apparatus according to the exemplary embodimentof the inventive concepts depending upon structure of light emittingdiode packages.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of various exemplary embodiments. It is apparent, however,that various exemplary embodiments may be practiced without thesespecific details or with one or more equivalent arrangements. In otherinstances, well-known structures and devices are shown in block diagramform in order to avoid unnecessarily obscuring various exemplaryembodiments.

In the accompanying figures, the size and relative sizes of layers,films, panels, regions, etc., may be exaggerated for clarity anddescriptive purposes. Also, like reference numerals denote likeelements.

When an element or layer is referred to as being “on,” “connected to,”or “coupled to” another element or layer, it may be directly on,connected to, or coupled to the other element or layer or interveningelements or layers may be present. When, however, an element or layer isreferred to as being “directly on,” “directly connected to,” or“directly coupled to” another element or layer, there are no interveningelements or layers present. For the purposes of this disclosure, “atleast one of X, Y, and Z” and “at least one selected from the groupconsisting of X, Y, and Z” may be construed as X only, Y only, Z only,or any combination of two or more of X, Y, and Z, such as, for instance,XYZ, XYY, YZ, and ZZ. Like numbers refer to like elements throughout. Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items.

Although the terms first, second, etc. may be used herein to describevarious elements, components, regions, layers, and/or sections, theseelements, components, regions, layers, and/or sections should not belimited by these terms. These terms are used to distinguish one element,component, region, layer, and/or section from another element,component, region, layer, and/or section. Thus, a first element,component, region, layer, and/or section discussed below could be termeda second element, component, region, layer, and/or section withoutdeparting from the teachings of the inventive concepts.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper,” and the like, may be used herein for descriptive purposes, and,thereby, to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the drawings. Spatiallyrelative terms are intended to encompass different orientations of anapparatus in use, operation, and/or manufacture in addition to theorientation depicted in the drawings. For example, if the apparatus inthe drawings is turned over, elements described as “below” or “beneath”other elements or features would then be oriented “above” the otherelements or features. Thus, the exemplary term “below” can encompassboth an orientation of above and below. Furthermore, the apparatus maybe otherwise oriented (e.g., rotated 90 degrees or at otherorientations), and, as such, the spatially relative descriptors usedherein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments and is not intended to be limiting. As used herein, thesingular forms, “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. Moreover,the terms “comprises,” “comprising,” “includes,” and/or “including,”when used in this specification, specify the presence of statedfeatures, integers, steps, operations, elements, components, and/orgroups thereof, but do not preclude the presence or addition of one ormore other features, integers, steps, operations, elements, components,and/or groups thereof.

Various exemplary embodiments are described herein with reference tosectional illustrations that are schematic illustrations of idealizedexemplary embodiments and/or intermediate structures. As such,variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, exemplary embodiments disclosed herein should not beconstrued as limited to the particular illustrated shapes of regions,but are to include deviations in shapes that result from, for instance,manufacturing. The regions illustrated in the drawings are schematic innature and their shapes are not intended to illustrate the actual shapeof a region of a device and are not intended to be limiting.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure is a part. Terms,such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and will not be interpreted in anidealized or overly formal sense, unless expressly so defined herein.

Exemplary embodiments of the inventive concepts will be described inmore detail with reference to the accompanying drawings.

FIG. 1A and FIG. 1B are top and bottom views of a display apparatusaccording to a first exemplary embodiment of the inventive concepts,respectively, and FIG. 2A and FIG. 2B are cross-sectional views of thedisplay apparatus according to the first exemplary embodiment of theinventive concepts.

A display apparatus 200 according to the first exemplary embodiment ofincludes light emitting diode packages 100, a front cover 230, a frame210, an optical part 220, and a light guide plate 240. Each of the lightemitting diode packages 100 includes a light emitting diode chip 112, areflector 114, and a molding part 116, which will be described below.

The front cover 230 may cover part of side and upper surfaces of adisplay panel 227 of the optical part 220. The front cover 230 may havea hollow center and the display panel 227 may be disposed at the centerof the front cover 230 such that an image displayed on the display panel227 can be viewed outside the display apparatus.

The frame 210 may support the display apparatus 200 and may be coupledto one side of the front cover 230. The frame 210 may be formed of asynthetic resin or a metallic material, such as Al alloys. The frame 210may be separated a predetermined distance from the optical part 220. Thelight emitting diode package 100 may be disposed on the frame 210 so asto face the optical part 220. Here, a distance between the frame 210 andthe optical part 220 may be an optical distance (OD) from the lightemitting diode package 100 to the optical part 220. In this exemplaryembodiment, the optical distance (OD) may be, for example, about 1 mm to15 mm.

The frame 210 may be provided at an upper side thereof with a substrate212, to which the light emitting diode package 100 is electricallyconnected. The substrate 212 serves to allow power supply to the lightemitting diode package 100 therethrough.

The optical part 220 is disposed above the frame 210, and includes aphosphor sheet 221, a diffusion plate 223, an optical sheet 225, and thedisplay panel 227.

The phosphor sheet 221 serves to perform wavelength conversion of lightemitted from the light emitting diode package 100. The phosphor sheet221 may contain at least one type of phosphor and may further include atleast one type of quantum dot (QD). In this exemplary embodiment, thelight emitting diode package 100 may emit blue light or UV light, andlight emitted through the phosphor sheet 221 may be white light.

The diffusion plate 223 serves to diffuse light in an upward directionupon receiving the light from the light emitting diode package 100.

The optical sheet 225 may be disposed on the diffusion plate 223 and thedisplay panel 227 may be disposed on the optical sheet 225. The opticalsheet 225 may include a plurality of sheets having different functions.For example, the optical sheet 225 may include one or more prism sheetsand diffusion sheets. The diffusion sheet can provide more uniformbrightness by preventing light emitted through the diffusion plate 223from being partially collected. The prism sheet can collect lightemitted through the diffusion sheet to allow the light to enter thedisplay panel 227 at a right angle.

The display panel 227 is disposed on an upper surface of the displayapparatus 200 and displays an image. The display panel 227 includes aplurality of pixels and can output an image corresponding to a color,brightness and chroma of each pixel.

As shown in FIG. 2A and FIG. 2B, the light guide plate 240 is interposedbetween the frame 210 and the optical part 220. The light guide plate240 serves to allow uniform emission of light towards the optical part220 upon receiving light. The thickness of the light guide plate 240 maybe the same as or less than an optical distance (OD), which is adistance between the frame 210 and the optical part 220. That is, theoptical distance corresponding to the distance from light emitting diodepackage 100 to the optical part 220 may be determined depending upon thethickness of the light guide plate 240. In addition, an air gap may beformed between the light guide plate 240 and the optical part 220.

The light emitting diode package 100 is disposed on the frame 210 andthe light guide plate 240 is disposed above the light emitting diodepackage 100. Here, the light guide plate 240 has a lower surfacedirectly contacting the frame 210 and may be formed with a light sourcegroove h placed corresponding to a location of the light emitting diodepackage 100. Accordingly, light emitted from the light emitting diodepackage 100 enters the light guide plate 240 through the light sourcegroove h.

Referring to FIG. 2A and FIG. 2B, the light source groove h may have aconcave shape and the shape of the light source groove h can be modifiedas needed. This will be described below. The number of light sourcegrooves h may correspond to the number of light emitting diode packages100.

Referring to FIG. 1A, the display apparatus 200 includes a plurality oflight emitting diode packages 100 regularly arranged thereon. By way ofexample, the light emitting diode packages 100 may be arranged in amatrix to be separated at constant intervals from each other.

FIG. 1A shows the structure wherein a plurality of light emitting diodepackages 100 is regularly arranged. The display apparatus 200 canprovide higher quality of HDR (high dynamic range) with increasingnumber of light emitting diode packages 100.

In addition, the display apparatus may be provided with a plurality ofpower supply units 250, which supply electric power to the plurality oflight emitting diode packages 100. Each power supply unit 250 can supplypower to at least one light emitting diode package 100. In thisexemplary embodiment, electric power is supplied to 32 light emittingdiode packages 100 through one power supply unit 250. Upon receivingelectric power from the power supply unit 250, the plurality of lightemitting diode packages 100 can emit light and be individually operated.

FIG. 3 is a sectional view of a light guide plate of the displayapparatus according to the first exemplary embodiment of the inventiveconcepts. The light guide plate 240 of the display apparatus 200 will bedescribed in more detail with reference to FIG. 3.

Referring to FIG. 3, a plurality of light emitting diode packages 100 isdisposed on the frame 210, and a relationship between one of the lightemitting diode packages 100 and the light guide plate 240 will bedescribed together with the shape of the light guide plate 240.

The light guide plate 240 is interposed between the frame 210 and theoptical part 220 and has a predetermined area to be disposed over theentirety of the display apparatus 200. The light guide plate 240 has asubstantially flat upper surface and may have a roughness R on the uppersurface thereof, as needed. The roughness R formed on the upper surfaceof the light guide plate 240 serves to diffuse light when the light isdischarged through the light guide plate 240. Thus, the roughness R maybe formed in a predetermined pattern or may be formed in an irregulardiffusion pattern. The irregular diffusion pattern may be formed throughcorrosion treatment with respect to the upper surface of the light guideplate 240.

The light guide plate 240 may be formed at a lower side thereof with thelight source grooves h. The number of light source grooves h maycorrespond to the number of light emitting diode packages 100 and eachof the light source grooves may have a concave shape. The light sourcegroove h may be configured to diffuse light in a lateral direction ofthe light source groove h when the light enters the light source grooveh. Thus, the depth of the light source groove h may be greater than thewidth thereof.

The light source groove h may have a width gradually decreasing from alower surface of the light guide plate 240 to an upper surface thereof,and may have a concave upper surface, without being limited thereto.Alternatively, the light source groove h may have a flat upper surface.That is, the light source groove h may have a bell-shaped cross-section.

By way of example, the light guide plate 240 may have a thickness t1 of0.5 mm to 3.0 mm and the light source groove h may have a depth t2corresponding to about 70% to about 80% of the thickness of the lightguide plate 240. For example, when the light guide plate 240 has athickness t1 of about 1.3 mm, the depth t2 of the light source groove hmay be about 0.9 mm.

The roughness R may have a thickness t3 of 5 μm to 500 μm, for example,about 170 μm.

FIG. 4 is a graph comparing light emission through the light guide plate240 when light is emitted from the light emitting diode packagesaccording to the first exemplary embodiment of the inventive concepts.

Referring to FIG. 4, in order to confirm uniformity of light emittedfrom the light emitting diode package 100 due to use of the light guideplate 240 according to the first exemplary embodiment, images of lightemitted from the light emitting diode packages 100 without passingthrough the light guide plate 240 are compared with images of lightemitted from the light emitting diode packages 100 and passing throughthe light guide plate 240. FIG. 4 shows images of light emitted fromnine light emitting diode packages 100, in which the OD is set to 2.8mm.

Referring to a left image of FIG. 4, which shows distribution of lightemitted from the nine light emitting diode packages without passingthrough the light guide plate, it can be confirmed that the lightemitted from the light emitting diode packages 100 is not spread and aspot is generated at each of the locations of the light emitting diodepackages 100.

Referring to a middle image of FIG. 4, which shows distribution of lightemitted from the nine light emitting diode packages and passing throughthe light guide plate 240 having a thickness of 1.5 mm, it can beconfirmed that the light emitted from the light emitting diode packages100 is more uniformly spread than the light shown in the left image andspots are partially generated at the locations of the light emittingdiode packages 100.

Referring to a right image of FIG. 4, which shows distribution of lightemitted from the nine light emitting diode packages and passing throughthe light guide plate 240 having a thickness of 2.8 mm, which is thesame as the optical distance (OD), it can be confirmed that the light ismore uniformly spread than the light shown in the left and middleimages.

That is, when light emitted from the light emitting diode packages 100is discharged through the light guide plate 240, as in this exemplaryembodiment, the light guide plate 240 spreads the light around the lightemitting diode packages 100, whereby the light can be uniformlydischarged through a light exit surface of the light guide plate 240.

FIG. 5 is a sectional view of the light emitting diode package of thedisplay apparatus according to the first exemplary embodiment of theinventive concepts.

Referring to FIG. 5, the light emitting diode package 100 according tothe first exemplary embodiment of the inventive concepts will bedescribed in more detail. As shown in FIG. 3, the light emitting diodepackage 100 includes a light emitting diode chip 112, a reflector 114,and a molding part 116.

The light emitting diode chip 112 may include an n-type semiconductorlayer, an active layer, and a p-type semiconductor layer. Here, each ofthe n-type semiconductor layer, the active layer, and the p-typesemiconductor layer may include a Group III-V-based compoundsemiconductor. For example, each of the n-type semiconductor layer, theactive layer, and the p-type semiconductor layer may include a nitridesemiconductor such as (Al, Ga, In)N.

The n-type semiconductor layer may be a conductive semiconductor layercontaining n-type dopants (for example, Si) and the p-type semiconductorlayer may be a conductive semiconductor layer containing p-type dopants(for example, Mg). The active layer is interposed between the n-typesemiconductor layer and the p-type semiconductor layer, and may have amulti-quantum well (MQW) structure. The composition of the active layermay be determined so as to emit light having a desired peak wavelength.

In this exemplary embodiment, the light emitting diode chip 112 may be aflip-chip type light emitting diode chip 112. In this structure, thelight emitting diode chip 112 may be provided at a lower side thereofwith an n-type electrode electrically connected to the n-typesemiconductor layer and a p-type electrode electrically connected to thep-type semiconductor layer.

When light is emitted from the light emitting diode chip 112, the lightis emitted through upper and side surfaces of the light emitting diodechip 112. In this exemplary embodiment, the light emitting diode chip112 may have a size of, for example, 670 μm×670 μm×250 μm(length×width×thickness).

The reflector 114 may be disposed on the light emitting diode chip 112so as to cover the entirety of an upper surface of the light emittingdiode chip 112. In this exemplary embodiment, the reflector 114 mayreflect light emitted from the light emitting diode chip 112 or mayallow some fractions of light emitted from the light emitting diode chip112 to be transmitted therethrough while reflecting the remainingfraction of the light.

By way of example, the reflector 114 may include a distributed Braggreflector (DBR). The distributed Bragg reflector may be formed byalternately stacking material layers having different indices ofrefraction. The distributed Bragg reflector can reflect the entirety orpart of light emitted from the light emitting diode chip 112 dependingupon the number of material layers constituting the distributed Braggreflector. In addition, the reflector 114 may include a metal or othermaterials, instead of the distributed Bragg reflector, as needed. Forexample, the reflector 114 may have a light transmittance of 0% to 80%.

Here, the distributed Bragg reflector may be formed through molecularbeam epitaxy, E-beam evaporation, ion-beam assisted deposition, reactiveplasma deposition, or sputtering.

Referring to FIG. 5, the molding part 116 may be disposed to cover theentirety of the light emitting diode chip 112, on which the reflector114 is disposed. That is, the molding part 116 may be disposed to coverthe upper and side surfaces of the light emitting diode chip 112excluding the n-type electrode and the p-type electrode disposed on thelower side of the light emitting diode chip 112.

The molding part 116 may be formed of a transparent material, forexample, silicone, so as to allow light emitted from the light emittingdiode chip 112 to pass therethrough.

In this exemplary embodiment, the molding part 116 is formed to coverthe light emitting diode chip 112 and may have a size of, for example,1,500 μm×1,500 μm×420 μm (length×width×thickness). That is, thethickness of the molding part 116 may be greater than or or equal to thesum of a thickness t of the light emitting diode chip 112 and athickness d1 (hereinafter, first thickness) of the molding part 116 fromthe upper surface of the light emitting diode chip 112 to an uppersurface of the molding part 116. Here, the first thickness d1 of themolding part 116 may be less than or equal to the thickness t of thelight emitting diode chip 112 (d1≤t).

In addition, a width d2 (hereinafter, first width) of the molding part116 from a side surface of the light emitting diode chip 112 to a sidesurface of the molding part 116 may be less than the first thickness d1.In this exemplary embodiment, the first width d2 of the molding part 116may be 1.5 times to 4 times, for example, about 2.44 times the firstthickness d1.

In other words, the molding part 116 is formed such that the thicknessd1 of the molding part 116 formed on the upper surface of the lightemitting diode chip 112 is less than the width d2 of the molding part116 formed on the side surface of the light emitting diode chip 112.Light emitted from the light emitting diode chip 112 is blocked by thereflector disposed on the upper surface of the light emitting diode chipand can be mostly emitted in the lateral direction of the light emittingdiode chip 112. Furthermore, light emitted from the light emitting diodechip 112 is guided by the shape of the molding part 116 formed on theupper and side surfaces of the light emitting diode chip 112 to be moreefficiently discharged in the lateral direction.

As such, since the light emitting diode package 100 including themolding part 116 formed to cover the light emitting diode chip 112allows light emitted from the light emitting diode chip 112 to bedischarged through the side surface thereof rather than the uppersurface thereof, the light emitting diode package can be used as a lightsource for a backlight unit of the display apparatus 200. Furthermore,when light is emitted from the light emitting diode package 100, thelight is refracted in the lateral direction while passing through thelight guide plate 240, thereby providing uniform light throughout thedisplay panel 227 of the display apparatus 200.

Particularly, since the light emitting diode package 100 allows light tobe discharged in the lateral direction thereof, it is possible to omit alens for diffusing light. In this exemplary embodiment, the light sourcegroove h of the light guide plate 240 can act as a lens. In a directtype backlight unit, the lens serves to spread light in the lateraldirection upon receiving light from the light emitting diode package100. According to this exemplary embodiment, since the light is spreadin the lateral direction of the light emitting diode package 100 whenthe light enters the light guide plate 240 through the light sourcegroove h of the light guide plate 240, it is possible to omit the needfor a separate lens.

As such, since the display apparatus 200 according to this firstexemplary embodiment does not employ a separate lens, it is possible tominimize the thickness of the display apparatus.

Further, the molding part 116 may be formed of a transparent materialalone, or may further include at least one type of phosphor or at leastone type of light diffuser for regulating light diffusion. In thisexemplary embodiment, since the optical part 220 includes the phosphorsheet 221 as described above, the molding part 116 can omit a separatephosphor. Alternatively, in order to improve color reproduction of lightemitted through the phosphor sheet 221 in the optical part 220, themolding part 116 may contain at least one type of phosphor.

In this exemplary embodiment, the light emitting diode package 100 isillustrated as including the light emitting diode chip 112, thereflector 114 and the molding part 116. Alternatively, at least one ofthe reflector 114 and the molding part 116 may be omitted.

Specifically, the light emitting diode package 100 may include the lightemitting diode chip 112 alone such that the light emitting diode chip112 is disposed in the light source groove h of the light guide plate240. With this structure, light emitted from the light emitting diodechip 112 can be spread in the lateral direction through the light guideplate 240.

Alternatively, the light emitting diode package 100 may include thelight emitting diode chip 112 and the reflector 114 without the moldingpart. With this structure, the reflector 114 can increase the amount oflight discharged in the lateral direction by reflecting more light inthe lateral direction than in the upward direction when the light isemitted from the light emitting diode chip 112.

FIG. 6 is a graph comparing light emission from the light emitting diodepackage according to the first exemplary embodiment of the inventiveconcepts.

FIG. 6 shows images and beam angles of light emitted from the lightemitting diode package according to the first exemplary embodiment ofthe inventive concepts. First, Images in (a) include far field data ofimages of light emitted from the light emitting diode chip 112 andphotographed at an OD of 0.4 mm, at an OD of 4 mm and at an OD of 50 cm,respectively. Images in (b) include far field data of images of lightemitted from the light emitting diode chip 112 with the reflector 114disposed on the upper side thereof, and photographed at an OD of 0.4 mm,at an OD of 4 mm and at an OD of 50 cm, respectively. Images in (c)include far field data of images of light emitted from the lightemitting diode chip 112 with the reflector 114 and the molding part 116disposed thereon, and photographed at an OD of 0.4 mm, at an OD of 4 mmand at an OD of 50 cm, respectively.

It can be confirmed from the images and the far field data that thereflector 114 and the molding part 116 formed on the light emittingdiode chip 112 allow uniform spreading of light emitted from the lightemitting diode package 100.

FIG. 7 is a sectional view of a light guide plate of a display apparatusaccording to a second exemplary embodiment of the inventive concepts.

A display apparatus 200 according to a second exemplary embodiment ofthe inventive concepts includes a light emitting diode package 100, afront cover 230, a frame 210, an optical part 220, a light guide plate240, and a reflection sheet 260. In description of the display apparatus200 according to this exemplary embodiment, descriptions of the samecomponents as those of the first exemplary embodiment will be omitted.

The following description will be given of features of the secondexemplary embodiment, that is, the light guide plate 240 and thereflection sheet 260, that are different from those of the firstexemplary embodiment with reference to FIG. 7.

The light guide plate 240 is interposed between the frame 210 and theoptical part 220 and serves to achieve uniform emission of light towardsan upper surface 247 of the light guide plate 240 by spreading lightemitted from a plurality of light emitting diode packages 100 disposedon the frame 210 in the lateral direction. To this end, the light guideplate 240 is provided at a lower side thereof with light source groovesh each receiving the light emitting diode package 100. As in the firstexemplary embodiment, the number of light source grooves h maycorrespond to the number of light emitting diode packages 100 and eachof the light sources h may have a concave shape. The concave shape ofthe light source groove is formed to spread light emitted from the lightemitting diode package 100 to a plane direction of the light guide plate240 and may have a bell shape, as shown in FIG. 7, or other shapes asneeded.

Although the depth and width of the light source groove h may be thesame as those of the light source groove h of the light guide plateaccording to the first exemplary embodiment, the depth of the lightsource groove h according to this exemplary embodiment may be less thanthe depth of the light source groove according to the first exemplaryembodiment. This structure results from the structure of the light guideplate having light exit grooves Eh formed above the light source groovesh.

Each of the light exit grooves Eh is formed above the light sourcegroove h and the number of light exit grooves Eh corresponds to thenumber of light source grooves h. Referring to FIG. 7, the light exitgrooves Eh may have a conical shape and have widths greater than thoseof the light source grooves h. In addition, the width of the light exitgroove Eh may be greater than the depth thereof.

Each of the light exit grooves Eh serves to reflect light on an innersurface thereof to spread in the lateral direction (plane direction) ofthe light guide plate 240 when the light emitted from the light emittingdiode package 100 enters the light guide plate 240 through the lightsource groove h.

Accordingly, an inner tip (vertex of the conical shape) of the lightexit groove (Eh) may have a gently curved surface instead of a sharpshape, or may have a flat surface as needed. In addition, although thelight exit groove Eh is shown as having a linear inclined surface 245 inthe cross-sectional view of FIG. 7, the light exit groove Eh may have aconcave inclined surface as shown in the inclined surface 245 of thelight source groove h, or a convex inclined surface as needed.

The uppermost end of the light exit groove Eh extends to the uppersurface 247 of the light guide plate 240. The upper surface 247 of thelight guide plate 240 may be a light exit surface through which thelight exits the light guide plate 240. In this exemplary embodiment, theupper surface 247 of the light guide plate 240 may be a substantiallyflat surface, without being limited thereto. Alternatively, the uppersurface 247 of the light guide plate 240 may not be flat or may have aroughness as needed.

With the structure wherein the light guide plate has the light exitgrooves Eh formed above light source grooves h as described above, lightemitted from the light emitting diode package 100 is spread over thelight guide plate 240 to be uniformly discharged through the uppersurface 247 of the light guide plate 240.

The reflection sheet 260 may be disposed on the lower surface of thelight guide plate 240. The reflection sheet 260 serves to increase theamount of light discharged through the upper surface of the light guideplate 240 when the light enters the light guide plate 240.

The reflection sheet 260 may have a thickness of, for example, about 120μm to 250 μm, which is similar to the thickness (for example, 150 μm to350 μm) of the light emitting diode package 100. Thus, the reflectionsheet 260 may be separated from the light emitting diode package 100 bya predetermined distance or more in order to prevent light emitted fromthe light emitting diode package 100 from being lost through reflectionby a side surface of the reflection sheet 260.

Further, since the light emitting diode package 100 and the light guideplate 240 are disposed on a substrate 212 mounted on the frame 210 andthe reflection sheet 260 is disposed on the lower surface of the lightguide plate 240, the lower surface of the light guide plate 240 has astep due to the thickness of the reflection sheet 260. That is, thelower surface of the light guide plate 240 includes a first lowersurface 241 and a second lower surface 243, and the step is formedbetween the first lower surface 241 and the second lower surface 243.

The first lower surface 241 may adjoin the substrate 212 on which thelight emitting diode chip 112 is disposed, and the second lower surface243 may adjoin the reflection sheet 260. As such, the step is formedbetween the second lower surface 243 and the first lower surface 241 dueto the thickness of the reflection sheet 260.

Furthermore, the first lower surface 241 may extend from a distal end ofthe light source groove h and an inclined surface 245 may be formedbetween the first lower surface 241 and the second lower surface 243.The inclined surface 245 serves to connect both ends of the step formedbetween the first lower surface 241 and the second lower surface 243.With this structure, light entering the light guide plate through thelight source groove h can be reflected by the inclined surface 245towards the upper surface of the light guide plate 240. Further, thestructure of the light guide plate including the inclined surface 245can prevent the light emitted from the light emitting diode chip 112from directly reaching the side surface of the reflection sheet 260,thereby minimizing loss of light through reflection by the side surfaceof the reflection sheet 260.

In other exemplary embodiments, the light guide plate may include theinclined surface 245 directly extending from the distal end of the lightsource groove h to the second lower surface 243 by omitting the firstlower surface 241, as needed.

As such, when light emitted from the light emitting diode chip 112received in the light source groove h of the light guide plate 240 onthe substrate 212 enters the light guide plate 240 through the lightsource groove h, the light can be discharged through the upper surface247 of the light guide plate 247 while being reflected by some portionsof the light guide plate 240 to spread in the lateral direction of thelight guide plate 240. Here, the light exit grooves Eh formed on thelight guide plate 240 and placed corresponding to the light sourcegroove h can improve efficiency of spreading light in the lateraldirection of the light guide plate 240.

Furthermore, the reflection sheet 260 disposed on the lower surface ofthe light guide plate 240 can increase the amount of light dischargedthrough the upper surface 247 of the light guide plate 240. In order toprevent loss of light emitted from the light emitting diode chip 112 dueto reflection by the side surface of the reflection sheet, the lightemitting diode chip 112 may be separated from the reflection sheet 260by a predetermined distance or more. Furthermore, the light sourcegroove h and the inclined surface 245 of the light guide plate 240 aredisposed between the light emitting diode chip 112 and the reflectionsheet 260 to prevent light emitted from the light emitting diode chip112 from directly reaching the side surface of the reflection sheet 260,thereby minimizing loss of light through reflection by the side surfaceof the reflection sheet 260.

FIG. 8 shows simulation images of light emitted from the displayapparatus according to the second exemplary embodiment of the inventiveconcepts.

FIG. 8 shows simulation results as to uniformity of light dischargedfrom the display apparatus 200 according to the second exemplaryembodiment of the inventive concepts, in which the light emitting diodepackages 100 are disposed. For simulation, the light guide plate 240 andthe reflection sheet 260 according to this exemplary embodiment weredisposed on the light emitting diode packages 100, and the light guideplate 240 was covered only by a brightness enhancement film (BEF) and adiffusion sheet. FIG. 8 shows only part of the display apparatus.

From the simulation results and the graphs in the x-axis and y-axisdirections shown in FIG. 8, it can be seen that the display apparatusgenerally had a light distribution of 9.56E+03 or more and the lightdistribution had a substantially linear shape both in the x-axisdirection and in the y-axis direction. Although only part of the displayapparatus 200 is shown in FIG. 8, it can be confirmed that the intensityof light was maintained at a certain level or higher and the light wasgenerally uniformly discharged through the display apparatus.

Accordingly, it can be seen that light emitted from the light emittingdiode packages 100 can be uniformly spread in the light guide plate 240and thus, can be uniformly discharged as surface light through the uppersurface 247 of the light guide plate 240, which is the light exitsurface.

FIG. 9A and FIG. 9B are top and bottom views of a display apparatusaccording to one exemplary embodiment of the inventive concepts,respectively, and FIG. 10A and FIG. 10B are cross-sectional views of thedisplay apparatus according to the exemplary embodiment of the inventiveconcepts.

A display apparatus 200 according to one exemplary embodiment of theinventive concepts includes light emitting diode packages 100, a frontcover 230, a frame 210, an optical part 220, and lenses 300. Each of thelight emitting diode packages 100 includes a light emitting diode chip112, a reflector 114, and a molding part 116, which will be describedbelow.

The front cover 230 may cover part of side and upper surfaces of adisplay panel 227 of the optical part 220. The front cover 230 may havea hollow center and the display panel 227 may be disposed at the centerof the front cover 230 such that an image displayed on the display panel227 can be viewed outside the display apparatus.

The frame 210 may support the display apparatus 200 and may be coupledat one side thereof to the front cover 230. The frame 210 may be formedof a synthetic resin or a metallic material such as an Al alloy. Theframe 210 may be separated a predetermined distance from the opticalpart 220. The light emitting diode package 100 may be disposed on theframe 210 so as to face the optical part 220. Here, a distance betweenthe frame 210 and the optical part 220 may be an optical distance (OD)from the light emitting diode package 100 to the optical part 220. Inthis exemplary embodiment, the optical distance (OD) may be, forexample, about 1 mm to 15 mm.

The frame 210 may be provided at an upper side thereof with a substrate212, to which the light emitting diode package 100 is electricallyconnected. The substrate 212 serves to allow power supply to the lightemitting diode package 100 therethrough.

The optical part 220 is disposed above the frame 210, and includes aphosphor sheet 221, a diffusion plate 223, an optical sheet 225 and thedisplay panel 227.

The phosphor sheet 221 serves to perform wavelength conversion of lightemitted from the light emitting diode package 100. The phosphor sheet221 may contain at least one type of phosphor and may further include atleast one type of quantum dot (QD). In this exemplary embodiment, thelight emitting diode package 100 may emit blue light or UV light, andlight emitted through the phosphor sheet 221 may be white light.

The diffusion plate 223 serves to diffuse light in an upward directionupon receiving the light from the light emitting diode package 100.

The optical sheet 225 may be disposed on the diffusion plate 223 and thedisplay panel 227 may be dispose on the optical sheet 225. The opticalsheet 225 may include a plurality of sheets having different functions.By way of example, the optical sheet 225 may include one or more prismsheets and diffusion sheets. The diffusion sheet can provide moreuniform brightness by preventing light emitted through the diffusionplate 223 from being partially collected. The prism sheet can collectlight emitted through the diffusion sheet to allow the light to enterthe display panel 227 at a right angle.

The display panel 227 is disposed on an upper surface of the displayapparatus 200 and displays an image. The display panel 227 includes aplurality of pixels and can output an image corresponding to a color,brightness, and chroma of each pixel.

In addition, the display apparatus may be provided with a plurality ofpower supply units 250, which supply electric power to the plurality oflight emitting diode packages 100. Each power supply unit 250 can supplypower to at least one light emitting diode package 100. In thisexemplary embodiment, electric power is supplied to 32 light emittingdiode packages 100 through one power supply unit 250. Upon receivingelectric power from the power supply unit 250, the plurality of lightemitting diode packages 100 can emit light and be individually operated.

Referring to FIG. 10A and FIG. 10B, each of the lenses 300 is disposedon the frame 210 between the frame 210 and the optical part 220. Thelens 300 serves to guide light emitted from the light emitting diodepackage 100 to travel in a lateral direction of the lens 300. Thisstructure will be described in detail with reference to FIG. 11.

FIG. 11 is a sectional view of a lens of the display apparatus accordingto the exemplary embodiment of the inventive concepts.

The lens 300 shown in FIG. 11 is provided for illustration only, and theshape of the lens 300 can be modified, as needed.

An optical distance (OD) corresponding to a distance from the frame 210to the optical part 220 can be adjusted depending upon the height of thelens 300. The lens 300 is disposed on the frame 210 such that an uppersurface 350 of the lens 300 closely adjoins the optical part 220.Alternatively, an air gap may be formed between the upper surface 350 ofthe lens 300 and the optical part 220. That is, the OD can be adjustedas needed.

Referring to FIG. 11, in this exemplary embodiment, the lens 300includes a lower surface 310, an upper surface 350, a flange 370, andlegs 390. The lower surface 310 may include a concave portion 320 and aninclined surface surrounding the concave portion 320. In some exemplaryembodiments, a flat surface may be disposed between the concave portion320 and the inclined surface, as needed.

The inclined surface serves to allow light emitted from the lightemitting diode package 100 and entering the lens 300 to be dischargedthrough a side surface of the lens 300 without total internalreflection, and an inclination of the inclined surface depends upon theshape of the lens 300.

The concave portion 320 defines a light incident face 330 through whichlight emitted from the light emitting diode package 100 enters the lens300. That is, the light incident face 330 is an inner surface of theconcave portion 320 and includes a side surface 330 a and an upper endportion 330 b. The concave portion 320 has a shape gradually decreasingin width from an entrance thereof in an upward direction. The sidesurface 330 a may have a constant inclination from the entrance of theconcave portion 320 to the upper end portion 330 b. Alternatively, theside surface 330 a may have an inclination gradually decreasing from theentrance of the concave portion 320 to the upper end portion 330 b. Thatis, the side surface 330 a may have a convex shape, as shown in FIG. 11.Referring to FIG. 11, the upper end portion 330 b may include a concavesurface or may have a flat surface, as needed.

A height of the concave portion 320 may be adjusted depending upon abeam angle of the light emitting diode package 100, the shape of theupper surface 350 of the lens 300, directional distribution of light,and the like.

The upper surface 350 of the lens 300 is configured to allow lighthaving entered the lens 300 to spread in a wide directionaldistribution, and acts as a light exit surface through which light exitsthe lens 300. By way of example, the upper surface 350 of the lens 300may include a concave surface 350 a near a central axis of the lens 300and a convex surface 350 b extending from the concave surface 350 a. Theconcave surface 350 a guides light traveling near the central axis ofthe lens 300 to be directed outwards, and the convex surface 350 bincreases the amount of light traveling outward from the central axis ofthe lens 300.

The flange 370 connects the upper surface 350 to the lower surface 310and defines the size of the lens 300. A side surface of the flange 370and the lower surface 310 may have a roughened pattern, as needed. Thelegs 390 of the lens 300 are coupled to the frame 210 to secure the lens300. By way of example, a leading end of each leg 390 may be bonded tothe frame 210 by a bonding agent and the like.

The light emitting diode package 100 described below may be disposed onthe frame 210 and the lens 300 may be disposed on the light emittingdiode package 100. Here, the lens 300 may be disposed on the frame 210such that the light emitting diode package 100 is placed inside theconcave portion 320. With this structure, light emitted from the lightemitting diode package 100 can enter the lens 300 through the lightincident face 330 of the concave portion 320.

In this exemplary embodiment, the number of lenses 300 may be the sameas the number of light emitting diode packages 100.

Referring to FIG. 9A, the display apparatus 200 includes a plurality oflight emitting diode packages 100 regularly arranged thereon. By way ofexample, the light emitting diode packages 100 may be arranged in amatrix to be separated at constant intervals from each other.

FIG. 9A shows the structure wherein a plurality of light emitting diodepackages 100 is regularly arranged. The display apparatus 200 canprovide higher quality HDR (high dynamic range) with increasing numberof light emitting diode packages 100.

FIG. 12 is a sectional view of a light emitting diode package accordingto one exemplary embodiment of the inventive concepts.

Referring to FIG. 12, a light emitting diode package 100 according toone exemplary embodiment of the inventive concepts disclosure will bedescribed in more detail. As shown in FIG. 12, the light emitting diodepackage 100 includes a light emitting diode chip 112, a reflector 114,and a molding part 116.

The light emitting diode chip 112 may include an n-type semiconductorlayer, an active layer, and a p-type semiconductor layer. Here, each ofthe n-type semiconductor layer, the active layer and the p-typesemiconductor layer may include a Group III-V-based compoundsemiconductor. By way of example, each of the n-type semiconductorlayer, the active layer and the p-type semiconductor layer may include anitride semiconductor such as AlN, GaN, or InN.

The n-type semiconductor layer may be a conductive semiconductor layercontaining n-type dopants (for example, Si) and the p-type semiconductorlayer may be a conductive semiconductor layer containing p-type dopants(for example, Mg). The active layer is interposed between the n-typesemiconductor layer and the p-type semiconductor layer, and may have amulti-quantum well (MQW) structure. The composition of the active layermay be determined so as to emit light having a desired peak wavelength.

In this exemplary embodiment, the light emitting diode chip 112 may be aflip-chip type light emitting diode chip 112. With this structure, thelight emitting diode chip 112 may be provided at a lower side thereofwith an n-type electrode electrically connected to the n-typesemiconductor layer and a p-type electrode electrically connected to thep-type semiconductor layer. When light is emitted from the lightemitting diode chip 112, the light is emitted through upper and sidesurfaces of the light emitting diode chip 112.

The reflector 114 may be disposed on the light emitting diode chip 112so as to cover the entirety of an upper surface of the light emittingdiode chip 112. In this exemplary embodiment, the reflector 114 mayreflect light emitted from the light emitting diode chip 112 or mayallow some fractions of light emitted from the light emitting diode chip112 to be transmitted therethrough while reflecting the remainingfraction of the light.

For example, the reflector 114 may include a distributed Bragg reflector(DBR). The distributed Bragg reflector may be formed by alternatelystacking material layers having different indices of refraction. Thedistributed Bragg reflector can reflect the entirety or part of lightemitted from the light emitting diode chip 112 depending upon the numberof material layers constituting the distributed Bragg reflector. Inaddition, the reflector 114 may include a metal or other materials,instead of the distributed Bragg reflector, as needed. For example, thereflector 114 may have a light transmittance of greater than 0% to lessthan 100%, for example, greater than 0% to 95%.

Here, the distributed Bragg reflector may be formed through molecularbeam epitaxy, E-beam evaporation, ion-beam assisted deposition, reactiveplasma deposition, or sputtering.

Referring to FIG. 13, the molding part 116 may be disposed to cover theentirety of the light emitting diode chip 112, on which the reflector114 is disposed. That is, the molding part 116 may be disposed to coverthe upper and side surfaces of the light emitting diode chip 112excluding the n-type electrode and the p-type electrode disposed on thelower side of the light emitting diode chip 112.

The molding part 116 may be formed of a transparent material, forexample, silicone, so as to allow light emitted from the light emittingdiode chip 112 to pass therethrough.

In this exemplary embodiment, the molding part 116 may be formed of atransparent material alone, or may further include at least one type ofphosphor or at least one type of light diffuser for regulating lightdiffusion. In this exemplary embodiment, since the optical part 220includes the phosphor sheet 221 as described above, the molding part 116can omit a separate phosphor. Alternatively, in order to improve colorreproduction of light emitted through the phosphor sheet 221 in theoptical part 220, the molding part 116 may contain at least one type ofphosphor.

In this exemplary embodiment, the light emitting diode package 100 isillustrated as including the light emitting diode chip 112, thereflector 114 and the molding part 116. Alternatively, at least one ofthe reflector 114 and the molding part 116 may be omitted.

Specifically, the light emitting diode package 100 may include the lightemitting diode chip 112 alone such that the light emitting diode chip112 is disposed in the concave portion 320 of the lens 300.

Alternatively, the light emitting diode package 100 may include thelight emitting diode chip 112 and the reflector 114 without the moldingpart. With this structure, the reflector 114 can increase the amount oflight discharged in the lateral direction by reflecting more light inthe lateral direction than in the upward direction when the light isemitted from the light emitting diode chip 112.

FIG. 13 shows an image of light emitted from a plurality of lightemitting diode packages, explaining uniformity of light emitted from thedisplay apparatus according to the exemplary embodiment of the inventiveconcepts. FIG. 14 shows images and graphs comparing uniformity of lightemitted from the display apparatus according to the exemplary embodimentof the inventive concepts depending upon structure of light emittingdiode packages and FIG. 15 shows graphs comparing directionalcharacteristics of light emitted from the display apparatus according tothe exemplary embodiment of the inventive concepts depending uponstructure of light emitting diode packages.

Next, uniformity and directional characteristics of light emittedthrough the light emitting diode package 100 and the lens 300 in thedisplay apparatus 200 according to the exemplary embodiment will bedescribed with reference to FIG. 14 and FIG. 15. Referring to FIG. 13,24 light emitting diode packages 100 are coupled to 24 lenses 300,respectively, and the optical distance OD is set to 3 mm.

FIG. 14 shows uniformity of light emitted from the display apparatusdepending upon the structure of the light emitting diode packages 100.The first image and graph show results measured using a structurewherein the light emitting diode chip 112 not including the reflector114 is disposed in the concave portion 320 of the lens 300 and theoptical part 220 including the diffusion sheet 223 and the phosphorsheet 221 is disposed above the lens 300. The second image and graphshow results measured using a structure wherein the light emitting diodepackage 100 including the reflector 114 having a reflectivity of 70% anddisposed on the light emitting diode chip 112 is disposed in the concaveportion 320 of the lens 300 and the optical part 220 including thediffusion sheet 223 and the phosphor sheet 221 is disposed above thelens 300. The third image and graph show results measured using astructure wherein the light emitting diode package 100 including thereflector 114 having a reflectivity of 95% and disposed on the lightemitting diode chip 112 is disposed in the concave portion 320 of thelens 300 and the optical part 220 including the diffusion sheet 223 andthe phosphor sheet 221 is disposed above the lens 300.

From the measurement results of uniformity obtained using the lightemitting diode packages 100 including the different reflectors 114, itcould be seen that the light emitting diode package 100 including thereflector 114 having a reflectivity of 95% provided a uniformity degreeof 95%, which was about 6% higher than the light emitting diode package100 not including the reflector 114.

In addition, referring to FIG. 15, from the measurement results of thedirectional characteristics of light, it could be seen that the lightemitting diode package 100 including the reflector 114 having areflectivity of 95% exhibited better spreading of light in the lateraldirection than the light emitting diode package 100 not including thereflector 114. In addition, although the light emitting diode package100 including the reflector 114 provided high light distributionefficiency, the light distribution efficiency of the light emittingdiode package 100 could be further improved through the lens 300 coupledthereto.

Although certain exemplary embodiments have been described herein, itshould be understood by those skilled in the art that these embodimentsare given by way of illustration only, and that various modifications,variations, and alterations can be made without departing from thespirit and scope of the invention. Therefore, the scope of the inventionshould be limited only by the accompanying claims and equivalentsthereof.

What is claimed is:
 1. A display apparatus comprising: a frame; aplurality of light emitting diodes regularly arranged on the frame; anoptical part disposed above the plurality of light emitting diodes andcomprising a display panel and at least one of a phosphor sheet and anoptical sheet; and a light guide plate disposed between the frame andthe optical part to cover the plurality of light emitting diodes,wherein the light guide plate comprises light source grooves placedcorresponding to locations of the plurality of light emitting diodes,respectively, such that light emitted from each of the light emittingdiodes enters the corresponding light source groove.
 2. The displayapparatus according to claim 1, wherein the light source groove has aconcave shape.
 3. The display apparatus according to claim 1, whereinthe light source groove has a flat upper surface.
 4. The displayapparatus according to claim 1, wherein the light guide plate comprisesa regular or irregular roughness formed on an upper surface thereof. 5.The display apparatus according to claim 4, wherein the roughness has athickness of 5 μm to 500 μm.
 6. The display apparatus according to claim1, wherein the light guide plate has a thickness of 0.5 mm to 3.0 mm. 7.The display apparatus according to claim 1, wherein the light sourcegroove has a depth corresponding to 70% to 80% of a thickness of thelight guide plate.
 8. The display apparatus according to claim 1,wherein the light emitting diode is a light emitting diode chip.
 9. Thedisplay apparatus according to claim 1, wherein each of the lightemitting diodes is a light emitting diode package, the light emittingdiode package comprising: a light emitting diode chip; and a reflectordisposed on an upper surface of the light emitting diode chip andconfigured to reflect at least part of light emitted from the lightemitting diode chip.
 10. The display apparatus according to claim 9,wherein the reflector comprises a distributed Bragg reflector.
 11. Thedisplay apparatus according to claim 9, wherein the reflector has atransmittance of 0% to 80% with respect to light emitted from the lightemitting diode chip.
 12. The display apparatus according to claim 9,wherein the light emitting diode package further comprises a moldingpart covering upper and side surfaces of the light emitting diode chipand the reflector.
 13. The display apparatus according to claim 12,wherein the molding part has a thickness from the upper surface of thereflector to an upper surface of the molding part that is less than awidth from the side surface of the light emitting diode chip to a sidesurface of the molding part.
 14. The display apparatus according toclaim 13, wherein the width of the molding part from the side surface ofthe light emitting diode chip to the side surface of the molding part is1.5 to 4 times the thickness of the molding part from the upper surfaceof the reflector to the upper surface of the molding part.
 15. Thedisplay apparatus according to claim 12, wherein the molding partcomprises at least one of at least one type of phosphor and at least onetype of light diffuser.
 16. The display apparatus according to claim 1,wherein the light guide plate comprises a light exit groove formed on anupper surface thereof and having a concave shape.
 17. The displayapparatus according to claim 16, wherein the light exit groove has aconical shape.
 18. The display apparatus according to claim 1, furthercomprising a reflection sheet interposed between the light guide plateand the frame and reflecting light inside the light guide plate in anupward direction.
 19. The display apparatus according to claim 18,wherein the reflection sheet is separated from the light emitting diodepackage.
 20. The display apparatus according to claim 18, wherein thelight guide plate comprises: a lower surface stepped from a distal endof the light source groove; and an inclined surface disposed between thelight source groove and the lower surface, and the lower surface adjoinsthe reflection sheet.
 21. The display apparatus according to claim 20,wherein the lower surface is a second lower surface and the light guideplate further comprises a first lower surface between the inclinedsurface and the light source groove.
 22. A backlight unit of a displayapparatus, comprising: a plurality of light emitting diodes; and a lightguide plate covering the plurality of light emitting diodes andconfigured to spread light emitted from the plurality of light emittingdiodes, wherein the light guide plate comprises light source groovesplaced corresponding to locations of the plurality of light emittingdiodes, respectively, such that light emitted from each of the lightemitting diodes enters the corresponding light source groove.
 23. Thebacklight unit according to claim 22, wherein the light source groovecomprises a flat upper surface.
 24. The backlight unit according toclaim 22, wherein the light guide plate comprises a regular or irregularroughness formed on an upper surface thereof.
 25. The backlight unitaccording to claim 22, wherein the light source groove has a depthcorresponding to 70% to 80% of a thickness of the light guide plate. 26.The backlight unit according to claim 22, wherein the light guide platecomprises a light exit groove formed on an upper surface thereof andhaving a concave shape.
 27. The backlight unit according to claim 22,further comprising a reflection sheet disposed on a lower surface of thelight guide plate and configured to reflect light inside the light guideplate in an upward direction.
 28. The backlight unit according to claim27, wherein the light guide plate comprises: a first lower surfaceextending from the light source groove; a second lower surface steppedfrom the first lower surface; and an inclined surface disposed betweenthe first lower surface and the second lower surface, and the secondlower surface adjoins the reflection sheet.
 29. A display apparatuscomprising: a frame; a plurality of light emitting diode packagesregularly arranged on the frame; an optical part disposed above theplurality of light emitting diode packages and comprising a displaypanel and at least one of a phosphor sheet and an optical sheet; and alens disposed between the frame and the optical part to cover each ofthe light emitting diode packages and configured to spread light emittedfrom the corresponding light emitting diode package, wherein each of thelight emitting diode packages comprises: a light emitting diode chip;and a reflector disposed on an upper surface of the light emitting diodechip and configured to reflect at least part of light emitted from thelight emitting diode chip.
 30. The display apparatus according to claim29, wherein: the lens comprises: a lower surface having a concaveportion defining a light incident face through which light enters thelens; and an upper surface through which light exits the lens; and thelight emitting diode package is disposed inside the concave portion ofthe lens.
 31. The display apparatus according to claim 30, wherein: thelight incident face of the lens comprises an upper end portion and aside surface extending from the upper end portion to an entrance of theconcave portion; and the concave portion has a width graduallydecreasing from the entrance thereof to the upper end portion.
 32. Thedisplay apparatus according to claim 31, wherein the side surface is aninclined surface having a constant inclination from the entrance of theconcave portion to the upper end portion or a curved inclined surfacehaving a gradually decreasing inclination from the entrance of theconcave portion to the upper end portion.
 33. The display apparatusaccording to claim 31, wherein the upper surface is a flat surface or acurved surface.
 34. The display apparatus according to claim 29, whereinthe reflector comprises a distributed Bragg reflector.
 35. The displayapparatus according to claim 34, wherein the reflector has atransmittance of greater than 0% and less than 100% with respect tolight emitted from the light emitting diode chip.
 36. The displayapparatus according to claim 29, wherein the light emitting diodepackage further comprises a molding part covering upper and sidesurfaces of the light emitting diode chip and the reflector.
 37. Thedisplay apparatus according to claim 36, wherein the molding partcomprises at least one of at least one type of phosphor and at least onetype of light diffuser.